A former London deputy mayor who resigned in the wake of claims over financial irregularities and was previously placed under Church of England disciplinary measures, has been appointed to a £100,000 pro rata job by London mayor Boris Johnson to work as a senior advisor on youth mentoring.

Lewis had also claimed he was a justice of the peace but the Ministry of Justice said he not been appointed as a magistrate.

In 2009 the Guardian also uncovered that he had used racist terminology whilst mentoring children.

On Tuesday the mayor's office said Lewis was now in charge of driving "the expansion of the mayor's mentoring programme" and would be paid £20,000 as a senior adviser, working one day a week at City Hall.

Lewis would also be advising the Greater London Authority on awarding up to £700,000 of youth mentoring funding, they said.

In a statement, the mayor of London said: "Ray Lewis has a wealth of experience helping vulnerable young men turn their lives around … As a passionate supporter of mentoring, I believe he is the right person to help us take forward our expansion in this area."

Speaking about his appointment Lewis said: "For many, mentoring can have a dramatic and positive effect, helping teenagers turn their backs on the lure of gangs or criminality. I look forward to helping the scheme expand and help fill our young men with the confidence to achieve great things through positive mentoring."

• This article was amended on 9 January 2013. The originally referred to the Greater London Authority as the Greater London Assembly.